Runtime components : Core components : Commands : Concepts : Command
  
Command
Action Abstract class
The action abstract class provides a default way to implement command interface. It has two parameters:
ID. It's used to identify the unit when in a complex flow.
Type. It's used to identify the type of Commands. In this toolkit, the following two types are reserved:
entry. It means that it will be executed when enter its parent.
exit. It means its parent should end after this command.
See the following code for example:
public class Journal extends Action<Map<String, Object>,String, Exception>{
  public String execute(Map<String, Object>context) throws Exception{
    Integer counter = (Integer) context.get("counter");
    counter = counter + 1;
    context.put("counter", counter);
    return "ok";
  }
}
It is totally stateless so please follow the stateless model such as do not call any APIs outside execute() etc, it’ll cause unpredictable result.
See also
Concepts